diff --git a/rsciio/dm5/_api.py b/rsciio/dm5/_api.py
index 7f0c464e..8631204a 100644
--- a/rsciio/dm5/_api.py
+++ b/rsciio/dm5/_api.py
@@ -256,8 +256,8 @@ def write_image(self, data, axes_dicts, metadata =None, brightness=None):
 
         image = Image(self.image_list[new_image_number], file=self.file)
         self.images.append(image)
-        navigation_dimensions = len([axis for axis in axes_dicts if axis["navigate"] == True])
-        signal_dimensions = len([axis for axis in axes_dicts if axis["navigate"] == False])
+        navigation_dimensions = len([axis for axis in axes_dicts if axis["navigate"]])
+        signal_dimensions = len([axis for axis in axes_dicts if not axis["navigate"]])
 
         image.update_data(data)
         for axis, axis_dict in enumerate(axes_dicts):
diff --git a/rsciio/tests/test_import.py b/rsciio/tests/test_import.py
index dbe849fb..149f6a2a 100644
--- a/rsciio/tests/test_import.py
+++ b/rsciio/tests/test_import.py
@@ -44,7 +44,7 @@ def test_import_all():
     # Remove plugins which require not installed optional dependencies
     h5py = importlib.util.find_spec("h5py")
     if h5py is None:
-        plugin_name_to_remove.extend(["EMD", "HSPY", "NeXus"])
+        plugin_name_to_remove.extend(["EMD", "HSPY", "NeXus", "DM5"])
 
     imageio = importlib.util.find_spec("imageio")
     if imageio is None: